Re: [RFC] should we care of COMPAT mode in bridge ?

[Eric Dumazet <eric.dumazet@gmail.com>]

Le lundi 06 juin 2011 à 22:26 +0200, Arnd Bergmann a écrit :
> On Monday 06 June 2011 22:12:54 Eric Dumazet wrote:
> > So for an old binary, compiled at the time SIOCBRADDBR wasnt there (in
> > include file I mean), we ended doing :
> > 
> >         {
> >                 char _br[IFNAMSIZ];
> >                 unsigned long arg[3]
> >                         = { BRCTL_ADD_BRIDGE, (unsigned long) _br };
> > 
> >                 strncpy(_br, brname, IFNAMSIZ);
> >                 ret = ioctl(br_socket_fd, SIOCSIFBR, arg);
> >         }
> > 
> > And this breaks on 64bit kernel
> 
> Ah, you were quicker than me at posting this ;-)
> 
> > I guess we shall add some logic in kernel to support SIOCSIFBR
> > afterall ;)
> > 
> > Thanks !
> > 
> > BTW: I confirm that compiling an up2date 32bit brctl with an up2date
> > include files is OK on 64bit kernel.
> 
> I did a little more digging in the history and found that the code in
> brctl was added in this commit:
> 
> commit 328f4711bbc369dcccf8f8cfba2adf5dd0f74479
> Author: shemminger <shemminger>
> Date:   Fri May 21 17:41:48 2004 +0000
> 
>     New version of command and library that use sysfs.
>     Update make system to build with or without sysfs.
> 
> It's not completely clear to me if it's worth supporting older
> user space than this, but it's certainly possible.
> 
> 	Arnd

In my case, I used latest bridge-utils tree, but compiled on a RHEL4
machine :)

# ls -l /usr/include/linux/sockios.h
-rw-r--r--  1 root root 5369 Mar 18  2002 /usr/include/linux/sockios.h
# rpm -qf /usr/include/linux/sockios.h
glibc-kernheaders-2.4-9.1.100.EL

Please note that pretty everything works on this 32bit distro machine,
but a 64bit kernel.